Cross-Site Scripting (XSS) in getkirby/cms (CVE-2026-45368)
Summary
Cross-site scripting in getkirby/cms (CVE-2026-45368). Risk of unauthorized operations or information disclosure. Exploitable via link. Mitigation: upgrade to 5.4.1 or later.
Original description
The description as published by the source.
Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, the underlying URL methods for the KirbyTags and image blocks components did not filter out malicious URL values that resolve to script execution. The vulnerability affects four first-party Kirby renderers that produce `` output from editor-supplied field values: the (link: …) KirbyTag, the link: parameter of the (image: …) KirbyTag when it does not resolve to a known file or self, the link field of the built-in image block, and the HTML importer for the blocks field (which accepted the same malicious input as the image block link field). While simple avascript: URLs were already deactivated by treating them as a relative path and prepending a single slash to the URL, the use of URLs of the format javascript://x%0A… bypasses this protection. The vbscript:, data:, livescript:, mocha: and jar: schemes are affected by the same underlying gap. This issue has been fixed in versions 4.9.1 and 5.4.1.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-45368 has been found in getkirby/cms.
Attackers can target a specific entry point like link over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade getkirby/cms to 5.4.1 or later.
If unsure, ask your IT team or search "getkirby/cms CVE-2026-45368" on the vendor's site.
CVE-2026-45368 (getkirby/cms) — CWE-79
Attack surface: link / self / blocks
Patched: 5.4.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in getkirby/cms. Attackers reach the vulnerable code path via link.
Check the vendor advisory for the affected versions of getkirby/cms. Attack surface: link / self / blocks.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 5.4.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'getkirby/cms' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'getkirby/cms' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
getkirby/cmsを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade getkirby/cms to 5.4.1ステージング環境で 5.4.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com